Not manufactured doubt (like the O. J. trial) where the principal objective is to invent reasons to believe or not believe in something. Manufactured doubt is the stock in trade of pseudoscientists.
Not doubt as a pretext for rationalization.
Not doubt born of insecurity. We've all had the experience of waiting for someone and starting to wonder if we had the right time or place. This sort of doubt means you're uncertain of your reasoning or your information, and the proper cure is to get sure. But if everything checks out, the proper course of action is to ignore the nagging doubts until persuasive evidence comes along that you might be wrong.
Doubt is constructive when it asks what the basis for a belief is. No belief system of any value can possibly be harmed by having to defend its reasoning and evidence.
In mathematics, there's a method of proof called reductio ad absurdum in which we assume the opposite of what we are trying to prove. It has been called the riskiest of all tactics; a gambit in chess merely offers a piece in exchange for an advantage, but reductio ad absurdum wagers the entire game.
The mathematician succeeds with reductio ad absurdum because he's willing to lay it all on the line. Sometimes he fails. A Jesuit mathematician named Saccheri tried in the 1700's to prove the famous Parallel Postulate in mathematics by this method. It didn't work; he never found a contradiction, and he lamely resorted to a rhetorical appeal to conclude his proof. To this day nobody is sure if Saccheri realized he was onto something or not, but a century later other mathematicians showed that it is possible to replace the Parallel Postulate with alternative assumptions and still create a consistent geometry (called non-Euclidean). A mathematician or a scientist thinks it's worth having to give up an assumption if that's the price of learning more.
In religion, even the existence of God needs to be up for debate. If you have real faith in your beliefs, you should have absolute confidence that you can pass any scrutiny. Even if you have to admit defeat in a debate, you should have faith that you will eventually find vindication.
One reason Darwin was such a shock to religious believers was that before Darwin, it was impossible to have a real, honest, debate about the existence of God. A nonbeliever who had the ill grace to win the debate would have been ostracized. So nonbelievers kept a low profile; debates were shams in which the outcome was never in doubt. Once Darwin advanced a theory that atheists could use to their advantage, believers were shocked. It seemed like atheists were everywhere. Where did they come from? They were there all along, just keeping a low profile.
Christianity was blindsided by Darwin because it never allowed real debate about its most fundamental dogmas and therefore had no idea where the weak spots were. It had absolutely no fallback plan for debating people who rejected its most basic assumptions, nor any experience in proving arguments to a skeptical audience. It also had no idea how extensive the opposition was.
Science is externally corrected, by data and observations. In science, if you take a wrong turn, you correct and little long-term harm is done; in religion the consequences may be more serious, so religions are conservative about modifying their beliefs in the face of external data (e.g., age of the earth, implications of population growth) but nobody can debate that they are overly conservative. Religions that absolutely reject external correction (Ken Ham's insistence that belief supersedes data) can be cults.
Religions give lip service to external testing but don't permit it in practice. For example, the Koran (10:38) challenges:
If they say: 'He invented it himself' [i.e. Mohammed wrote the Koran himself] say: 'Bring me one chapter like it. Call on whom you may besides God to help you, if what you say be true." (N.J. Dawood translation).
So ostensibly, if you could produce anything comparable to the Koran, that would be proof of the Koran's human origins. Except we all know what would happen to anyone who dared say he had written something equal to the Koran.
The Bible also contains challenges, like this one in Malachi 3:10:
Bring the whole tithe into the storehouse, that there may be food in my house. Test me in this," says the LORD Almighty, "and see if I will not throw open the floodgates of heaven and pour out so much blessing that you will not have room enough for it.
This verse is a staple in many conservative churches as support for the concept of tithing. What do you suppose would happen if someone claimed to have tithed regularly and gotten into financial difficulty as a result? Would we see acknowledgement that the test had failed? Or would we see rationalizations that the person hadn't really tithed, or lost faith and didn't continue long enough? Why is it that the faithful are supposed to rely on God for prosperity, but we never see a church with enough faith not to take collections?
Science is internally corrected by peer review and debate. Internal correction is the institutional response to external correction.
In theory, religions also have internal corrective systems. The Catholic Church has councils, Protestants simply fission off new denominations, but in fact, neither really have effective ways to consider whether they might have serious problems that require radical (in the sense of at the roots) changes in doctrines. Where is the mechanism among Protestant fundamentalists for really, objectively analyzing the doctrine of Biblical inerrancy? Or the Catholic mechanism for re-examining Papal infallibility? Some groups utterly reject any kind of correction (often the leadership is the source of all authority) and that can make them cults.
Science has the discipline to say that some questions simply cannot be answered. Sometimes the data is irretrievably lost; we will never have a complete inventory of all the species that ever lived, or know what the landscape looked like in the past if there were no rocks from that time preserved. For example, some astronomers recently used astronomical software to re-examine Greek writings to understand why the runner from Marathon collapsed and died. A marathon run was no big deal to trained couriers in those days and this one had run over 100 miles in the previous week delivering messages. The astronomers hypothesized that the traditional date of the battle might have been one lunation off, meaning the battle took place a month earlier in the summer and the runner had to contend with hot weather. But the runner could have had an undetected aneurysm that burst, or a blood clot that caused a heart attack or stroke, or some congenital heart abnormality, or been bitten or stung by something, or even eaten something that gave him food poisoning. The bottom line is that we will probably never be able to answer this question and we just have to live with it.
Sometimes the data are insufficient and there is nothing we can do to acquire more data. We have no firm evidence one way or the other if extraterrestrial intelligence exists, and there is nothing we can do to find out, except wait until we discover a signal. The late Carl Sagan often noted that people were never satisfied when he answered that we don't really know whether extraterrestrial life exists; they would always press on with "but what do you think?" We scientists would like to believe we will someday get to the stars but all the odds are that it will take centuries at least to do it, and it may never be possible. Until then, we have to live with the fact that we cannot get there. As a geologist, I am not the least bit happy that most of the earth's history is gone beyond recovery, but I have to accept it. Sometimes we come up with creative ways to discover information that was previously believed unobtainable, but there are problems where the difficulties are so formidable that we have good reason to believe we cannot get around them, period.
When knowledge of the earth was incomplete, mapmakers found it intolerable that vast areas were blanks and invented fictitious lands or filled in blanks with legendary features. The idea that so much of the earth was unknown was intolerable.
Religion speaks of mysteries in theory, like how to reconcile infinite justice with infinite mercy, or how to mesh God's knowledge of all things with free will, but regardless of what theologians say, many people are incapable of accepting that some things just cannot be known. The actual amount of information about the supernatural in the Bible or the Quran is actually very limited, so throughout history people have filed the gaps with endless elaborate speculations on what Heaven and Hell are like, the orders of angels, the end times, and so on. People who get obsessed with these speculations, especially when they become militant, can cross the line into cultism. The speculations ultimately do more harm than good. Since they are pure speculation with no prospect of actually being tested, they can never contribute anything positive to our knowledge. Furthermore, they have a way of hardening into doctrines which at best are unsupported and at worst (most of the time) are wrong.
The actual information Christianity has about God and the supernatural is all contained in one book. All those shelves and shelves of books in the average religious bookstore are mostly empty speculation. "Resounding gongs" and "clanging cymbals" (1 Cor. 13:1)
Then we have the speculations and theories that are downright stupid. The worst offenders are the books that say God "had" to do something a particular way. Had to? Gee, I thought an omnipotent God could do anything.
In the military, there's a concept called "need to know." Just because you have a top-secret clearance doesn't give you a license to go into a file cabinet and start rummaging through classified information. You have to demonstrate that the information is pertinent to your own mission to access it. Religious believers need to accept that they need to know only the specific things God requires them to know (which is a miniscule amount of information), and that beyond that, they have no need, or right, to know.
1 Everyone must submit himself to the governing authorities, for there is no authority except that which God has established. The authorities that exist have been established by God. 2 Consequently, he who rebels against the authority is rebelling against what God has instituted, and those who do so will bring judgment on themselves. 3 For rulers hold no terror for those who do right, but for those who do wrong. Do you want to be free from fear of the one in authority? Then do what is right and he will commend you. (Romans 1:3)
Obey your leaders and submit to their authority. They keep watch over you as men who must give an account. Obey them so that their work will be a joy, not a burden, for that would be of no advantage to you. (Hebrews 13:17)
13 Submit yourselves for the Lord's sake to every authority instituted among men: whether to the king, as the supreme authority, 14 or to governors, who are sent by him to punish those who do wrong and to commend those who do right. (1 Peter 2:13-14)
Although religions give lip service to the idea of legitimate secular authority, you don't need to read very much religious literature to find it seething with resentment of authority.
Science can say what is, not what ought to be. The fact that a fetus has fingerprints a few weeks into gestation doesn't prove abortion is wrong, and evidence that fetuses lack organized nervous systems doesn't prove abortion is right. Science can inform moral decisions; it can show that some desirable things are impossible and some harmful things are inevitable, but the moral decisions have to come from somewhere else.
However, when it comes to saying what is, how the physical world works and how it has evolved, science, not religion, is the lawful authority.
Created 12 October, 2005; Last Update 02 June, 2010
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